Use GGX instead of Blinn-Phong, and use a specular map. That should get you 95% of the way there, although Cryengine uses a slightly different tangent basis and roughness curve.
Yeah, cry's roughness curve is crazy. Also their fresnel is completely different.. Its not impossible to get the same shader, just requires a new brdf if you want something even 95% the way there. not to mention cry's lighting render pipe is never consistent. so... yeah.